B cell superantigens subvert innate functions of B cells

Some infectious agents produce molecules capable of interacting specifically with the immunoglobulin variable regions, independently of the conventional binding site. They are referred to as B cell superantigens, and include protein A of Staphylococcus aureus, protein L of Peptostreptococcus magnus, and gp120 of HIV-1. To test their effects in vivo, we used transgenic mice whose immunoglobulin loci were inactivated and their humoral immune system had been restored by introduction of human immunoglobulin loci. We found that administration of soluble recombinant B cell superantigens can deplete B cell subsets in vivo. They also preferentially impact B cell subpopulations responsible for innate-like functions. The studies indicate that certain pathogens have evolved primarily to subvert innate functions of B cells.